Packaging

ABSTRACT

Packages having a base web ( 2 ) consisting of a polymeric film or sheet having at least one recess ( 3 ) with a packaged item therein, and a sealing web ( 4 ) sealed to the base web ( 2 ) and covering the recess ( 3 ), the sealing web ( 4 ) having a strength which substantially prevents the packaged item from being pushed through it on applying force to the recess ( 3 ) in the base web ( 2 ). A portion of the package where the base web ( 2 ) is sealed to the sealing web ( 4 ) has two substantially parallel lines of weakness ( 11, 12 ) positioned so that said portion can be folded towards a portion of the sealing web ( 4 ) and a corner of the package can be used to puncture the sealing web ( 4 ) so that the packaged item can then be pushed through the sealing web ( 4 ).

This invention concerns packaging and more particularly tamper resistantpackaging.

Tamper resistant packaging is becoming ever more in demand in order toreduce the risk of unauthorised access to packaged products, either toreduce the risk of tampering with the product itself or indeed itsremoval. The latter is of particular concern with packagedpharmaceutical products and the possibility of children eating them.

Various proposals have been made hitherto for reducing the risk ofchildren gaining access to pharmaceutical products, for example usingcontainers which require a special technique to open them, e.g. using aclutch operated screw cap. However, whilst such containers are generallyeffective in making it difficult for children to gain access to theircontents, they are also difficult to open by the people for whom thepharmaceutical products have been prescribed.

Instead of using containers with screw caps, pharmaceuticals areincreasingly packaged in pop-through packages where each dosage unit islocated in a recess in a flexible plastics base web, the recesses in thebase web being sealed by a membrane, usually aluminum foil, throughwhich the dosage unit can be pressed when required by pressing on therecesses. These packages have a number of advantages, such as the easeof determining correct filling of all of the recesses and counting thenumber of dosage units which have been taken. However, the ease ofpressing the dosage units through the sealing membrane makes them poorat resisting unauthorised access.

Such packages can be provided with improved tamper resistance, forexample by making the sealing membrane tougher. However, toughening themembrane also increases the force required to push the packaged productthrough the membrane to the point where this is impossible.

The present invention seeks to overcome or at least ameliorate thedisadvantages of such packaging.

According to the present invention there is provided a packagecomprising a base web comprising a polymeric film or sheet having atleast one recess therein and with a packaged item therein, and a sealingweb sealed to the base web and covering the recess, the sealing webhaving a strength which substantially prevents the packaged item frombeing pushed therethrough on applying force to the recess in the baseweb, a portion of the package where the base web is sealed to thesealing web having two substantially parallel lines of weaknesspositioned so that said portion can be folded towards a portion of thesealing web and a corner of the package can be used to puncture thesealing web so that the packaged item can then be pushed through thesealing web.

As will be appreciated, packages in accordance with the presentinvention can be made from a variety of materials.

Subject to physical considerations which will be discussed subsequently,the base web can be made from any polymeric material used for blisterpackaging. Preferred materials for the base web are thermoformablepolymer films or sheets, for example films or sheets of polyvinylchloride.

The thickness of the base web can in general be selected according tocriteria used hitherto for base webs for blister packaging, for examplefrom 190 to 300 μm, subject to the combined stiffness of the base weband adhered sealing web, and its ability to puncture the sealing web aswill subsequently be described in more detail.

The sealing web should be sufficiently strong that it effectivelyprevents packaged articles from being pushed therethrough without aninitiating cut therein, but allow them to be pushed therethrough oncethe integrity of the sealing web over a particular recess in the baseweb has been compromised.

Sealing webs of packages in accordance with the present inventionpreferably have low permeability to oxygen and moisture. In hithertoproposed blister packages this has generally been provided by the use ofa metal foil which is thin enough to allow packaged articles to bepushed therethrough. However, the present invention uses a sealing webwhich is stronger than hitherto proposed sealing webs, and so resistspackaged articles being pushed through the sealing web.

Preferred sealing webs for packages in accordance with the presentinvention consist of a laminate of a metal foil, preferably aluminumfoil, adhered to a strengthening polymeric layer which imparts therequired additional strength to the sealing web. Preferred polymericlayers for the purpose include those made from polyesters, e.g.polyethylene terephthalate, polyamides and polyolefins, e.g.polypropylene.

Where necessary, the metal foil can be adhered to the strengtheningpolymeric layer using a water or organic solvent based laminatingadhesives containing polyurethane or polyethyleneimine, or using anextrudable tie or adhesive layer, for example a maleic anhydridemodified polyethylene.

The sealing web of packages of the present invention will in general besealed to the base web so that the strengthening polymeric layer of theformer is external relative to the metal foil. In general, this sealingwill require the presence of a tie or adhesive layer which will usuallybe applied to the metal foil prior to sealing of the sealing web to thebase web. However, the base web could be provided with an outer layer ofa tie or adhesive layer. Materials for effecting sealing of the metalfoil to the base web include ethylene/vinyl acetate and ethylene/acrylicacid based adhesive dispersions.

As indicated above, the sealing web should have a strength whichsubstantially prevents packaged articles from being pushed therethroughbut should also be capable of being punctured by a combination of thebase web sealed to the sealing web. The thicknesses of the variouslayers of the sealing web can therefore be varied in order to achievethis effect. However, the metal foil will usually be of a thicknesssubstantially that used hitherto for pop-through packages, for examplefrom 20 to 30 μm. The strengthening polymeric layer is preferably from10 to 50 μm, and more preferably from 10 to 30 μm.

The tie or adhesive layer used to adhere the metal foil to thestrengthening polymeric layer will usually be less than 5 μm thick.

The adhesive layer used to adhere the sealing web to the base web willusually be less than 10 μm thick, and preferably be about 5 μm thick.

Packages in accordance with the present invention can be produced byknown methods. Thus the base web can be produced by thermoforming asuitable polymeric film or sheet to produce recesses for the articles tobe packaged. The sealing web can also be produced using known methodsaccording to the particular structure of the web. Sealing websconsisting of a metal foil adhered to a polymeric strengthening layercan be formed, for example, by adhesion laminating a pre-formedstrengthening layer to a metal foil using a tie or adhesive layer, or bypre-coating the metal foil with a tie or adhesive layer and using thetie or adhesive layer to adhere the metal foil to the strengtheninglayer.

The adhesive layer used to adhere the metal foil to the base web will ingeneral be applied as a pre-coat to the metal foil before the sealingweb is adhered to the base web.

In order to provide corners of regions of packages of the presentinvention where the base and sealing webs are sealed together withsufficient strength to puncture the sealing webs, these sealed regionsthemselves tend to be sufficiently stiff that they cannot be bent aroundto effect the puncturing. The present invention therefore provides atleast two lines of weakness which allow a corner of the packages to bebent along these lines so that a corner of the packages can effect thenecessary puncturing.

The position of the lines of weakness relative to an associated cornerof the packages can generally be varied, provided the desired puncturingcan be effected.

An embodiment of package in accordance with the present invention willnow be described with reference to the accompanying drawings in which:

FIG. 1 is a plan view of the embodiment with a plurality of sealedblisters;

FIG. 2 is a plan view of a single sealed blister of the embodiment priorto opening;

FIG. 3 corresponds to FIG. 2 during an initial phase of opening of thesingle blister;

FIG. 4 is a perspective view corresponding to FIG. 3;

FIG. 5 corresponds to FIG. 2 during a further stage of opening of theblister;

FIG. 6 is a perspective view corresponding to FIG. 5;

FIG. 7 is a side view corresponding to FIGS. 5 and 6;

FIG. 8 is a plan view of the blister during piercing of the blister; and

FIG. 9 is a plan view of the blister after piercing has taken place.

The package shown generally at 1 in FIG. 1 consists of a thermoformedbase web 2, having eight recesses 3 therein, with a sealing web 4 heatsealed thereto. The size, shape and number of recesses 3 can be variedaccording to the number of articles to be packaged by the package.

The package 1 is divided into eight individual blister packs 5 which areconnected to each other along tear lines 6, 7, 8 and 9 which allowindividual blister packs 5 to be separated from the others, for examplewhen packaged articles (not shown) within the recesses 3 are to beremoved therefrom. FIGS. 2-9 show one such blister package 5 separatedfrom the other seven shown in FIG. 1.

A corner region 10 of the blister package 5 shown in FIGS. 2-9 has twosubstantially parallel lines of weakness 11 and 12 formed thereinsubstantially parallel to the circumference of the recess 3, for exampleby heating, which allow the region 10 to be folded as shown in FIGS.3-9. The first fold is shown along the line 11, with the second foldbeing along the line 12.

As will be appreciated, the folds could be made in the reverse order.

As can be seen from FIGS. 5-7, this folding process produces a spike 13for puncturing the sealing web 4, further folding along the line 11resulting in the spike 13 effecting puncturing as shown in FIG. 8 toform a cut 14 in the sealing web 4 covering the recess 3.

The cut 14 weakens the sealing web 4 and enables the packaged article tobe pushed therethrough.

The production of a package 1 will now be described by way of exampleonly.

EXAMPLE

A sealing web for the package was produced by coating one side of a 23μm thick aluminum foil with 1 μm of a tie layer and using the tie layerto adhere the foil to a 12 μm thick layer of cast polyethyleneterephthalate. The free surface of the aluminum foil was then coatedwith 5 μm of the adhesive tie layer material. The puncture resistance ofthe uncoated aluminum foil was 8.729N (standard deviation 1.82), that ofthe cast polyethylene terephthalate was 2.79N and that of the laminateof the aluminum foil to the cast polyethylene terephthalate was31.97N(standard deviation 3.47), the test being effected according toASTM D3763 and a speed of 20 inches/minute (50.8 cm/min).

A base web was produced by thermoforming a 190 μm thick sheet ofpolyvinyl chloride to produce eight recesses into which articles to bepackaged were inserted. The adhesive coated surface of the sealing webwas then heat sealed to the base web using heat seal jaws at atemperature of 140° C. and a dwell time of 1 sec.

During the package manufacturing process, tear lines 6-9 were producedby perforation through the sealing web 4 and the base web 2, and thelines of weakness or fold lines 11 and 12 were produced by heating thetwo webs along these lines to thermoform the ridges into the baseweb.

1. A package comprising a base web comprising a polymeric film or sheethaving at least one recess therein and with a packaged item therein, anda sealing web sealed to the base web and covering the recess, thesealing web having a strength which substantially prevents the packageditem from being pushed therethrough on applying force to the recess inthe base web, a portion of the package where the base web is sealed tothe sealing web having two substantially parallel lines of weaknesspositioned so that said portion can be folded towards a portion of thesealing web and a corner of the package can be used to puncture thesealing web so that the packaged item can then be pushed through thesealing web.
 2. A package according to claim 1, wherein the sealing webcomprises a metal foil adhered to a polymeric web.
 3. A packageaccording to claim 2, wherein the metal foil comprises aluminum.
 4. Apackage according to claim 2, wherein the polymeric web comprisespolyethylene terephthalate.
 5. A package according to claim 1, whereinthe polymeric film or sheet comprises polyvinyl chloride.
 6. A packageaccording to claim 1, wherein the polymeric film or sheet has beenthermoformed.
 7. A package according to claim 1, wherein the polymericfilm or sheet has been heat sealed to the sealing web.